PSA: The meaning of "Counterplay"
Pressing a button isn't counterplay.
Buying an item isn't counterplay.
Counterpicking isn't counterplay.
Counterplay means doing something skillful to negate an opponent's skillful move. Vayne tumble is counterplay to skillshots, because it requires (some) skill to aim a skillshot, and it requires (some) skill to tumble out of its way. Using cleanse is counterplay to Thresh hooks, because it comes down to who presses their button first after Thresh lands the hook.
But buying armor is not counterplay to Talon, because buying armor does not require any skill. That's just a counter. Talon was nerfed because he had only counters (strong ones) but no counterplay. Same for Leblanc.
And Sion was given counterplay (which amounted to a nerf) because there was no way to outplay a targetted stun and burst if you were melee, whereas ranged nukers could just poke him down. It came down to which champion you picked, and picking the right champion doesn't require skill.
The more you know!